GM Service Manual Online
For 1990-2009 cars only

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

  1. Turn ignition ON
  2. Place transmission in neutral.
  3. Place headlamp switch in the AUTO/OFF position.

All exterior lamps off.

Headlamps on. Refer to Headlamps Inoperative in Low Light Conditions . Marker lamps on. Refer to Marker Lamps Inoperative . Instrument panel on Refer to Instrument Panel Lamps Inoperative .

2

  1. Turn ignition ON
  2. Set park brake
  3. Place transmission in neutral.
  4. Place headlamp switch in the AUTO/OFF position.

(Day light conditions). All exterior lamps off.

Headlamps on. Refer to Headlamps Inoperative in Low Light Conditions . Marker lamps on. Refer to Marker Lamps Inoperative . Instrument panel on Refer to Instrument Panel Lamps Inoperative .

3

  1. Turn ignition ON
  2. Place transmission in neutral.
  3. Place headlamp switch in the AUTO/OFF position.
  4. Cover the ambient light sensor.

Headlamps and front and rear marker lamps turn on.

Headlamps do not turn on. Refer to Headlamps Inoperative in Low Light Conditions . Marker lamps do not turn on. Refer to Marker Lamps Inoperative .

4

  1. Turn ignition ON
  2. Place transmission in neutral.
  3. Place headlamp switch in the AUTO/OFF position.
  4. Expose the ambient light sensor to a bright incandescent light.

After a few seconds all exterior lamps turn off.

Headlamps on. Refer to Headlamps Inoperative in Low Light Conditions . Marker lamps on. Refer to Marker Lamps Inoperative . Instrument panel on Refer to Instrument Panel Lamps Inoperative .

5

  1. Turn ignition ON
  2. Turn headlamp switch to the ON (HEAD) position.

Headlamps turn on. Marker lamps and tail lamps turn on.

Headlamps off. Refer to Headlamps Inoperative in Low Light Conditions .Marker lamps do not turn on. Refer to Marker Lamps Inoperative .

6

  1. Turn ignition ON
  2. Turn headlamp switch to the ON (HEAD) position.
  3. Cycle the low and high beams with the multifunction switch.

Headlamps turn on. Marker lamps and tail lamps turn on. Headlamps switch from low beam to high beam.

Headlamps do not turn on. Refer to Headlamps Inoperative in Low Light Conditions . Headlamps do not switch Intensity, both high beam and low beam on. Refer to Headlamps Inoperative - Low Beams Headlamps Inoperative - High Beams . Marker lamps do not turn on. Refer to Marker Lamps Inoperative .

7

  1. Turn ignition ON
  2. Cycle the flash to pass function with the multifunction switch.

Headlamps flash on and off.

Flash to pass inoperative. Refer to Headlamps Flash to Pass Inoperative